18837745666 has 4 divisors (see below), whose sum is σ = 28256618502. Its totient is φ = 9418872832.

The previous prime is 18837745649. The next prime is 18837745691. The reversal of 18837745666 is 66654773881.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 18540907225 + 296838441 = 136165^2 + 17229^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4709436415 + ... + 4709436418.

Almost surely, 2^18837745666 is an apocalyptic number.

18837745666 is a deficient number, since it is larger than the sum of its proper divisors (9418872836).

18837745666 is an equidigital number, since it uses as much as digits as its factorization.

18837745666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9418872835.

The product of its digits is 40642560, while the sum is 61.

The spelling of 18837745666 in words is "eighteen billion, eight hundred thirty-seven million, seven hundred forty-five thousand, six hundred sixty-six".